Simply so, how long does a 3ds XL battery last?
3.5 to 6.5 hours
Also to know is, how do I know when my 3ds XL is fully charged?
The orange light only turns on while your system isplugged in, and will only turn off once the system is fullycharged. In short, if your 3DS is plugged in, and yousee an orange light, it's NOT fully charged. If your3DS is plugged in, and you DO NOT see an orange light, it ISfully charged.
Once it is fully charged, the system stops thecharger from putting more energy into the battery. If you plug inon a full charge, the system just runs off the AC adapterinstead of draining the battery. It is obvious to design devices towork this way.